This is a really simple one. The long rant is below.
PUT MORE STUFF IN SPACE.
In GC2 the map was basically empty and immutable - there were a total of 5 objects: Suns, planets, asteroids, anomalies and ships, 3 of which were completely static(excluding the gimicky death star).
And yet on the scales GC purports to operate, there is SO MUCH STUFF in space.
Nebulas to hide starbases, or from which pirates can pester you.
Asteroid bases to launch pirate attacks from.
Dark matter clouds that can hold rare resources or your doom.
Black holes for navigational hazards(better make sure you have your graviton sensors if venturing into deep space).
Pulsars which can emit GRB's.
Stellar nurseries for the flavor.
The occasional supernova for the excitement.
...and all sorts of others.
Also, for the love of all that's holy - keyboard shortcuts for EVERYTHING! PLEASE!
It's always a mild shock to my system when I transition from Civ to GalCiv.